Acknowledgments

We thank C. Ross, D. Krause, M. Silcox, and E. Sargis for their helpful comments and for reviewing the manuscript. We also thank K. C. Beard, D. Fisher, D. Fox, E. Kowalski, K. Rose, W. Sanders, R. Secord, F. Szalay, J. Trapani, P. Houde, J. Wilson, I. Zalmout, and the participants of the Primate Origins Conference for many helpful conversations. We especially thank G. Gunnell and P. Gingerich for their tremendous help and support during this ongoing project and for access to the unpublished skeleton of Plesiadapis cookei. We thank M. Dagosto and M. Ravosa for inviting us to be part of this symposium. Research was supported by grants from the National Science Foundation: BCS-0129601 and EAR-0308902.